U.S. Pat. No. 6,126,852 is aimed at acid based antifreeze formulations. The acids are monobasic aliphatic organic acids or the alkali metal salts thereof.
U.S. Pat. No. 5,076,951 teaches polyhydric alcohol antifreeze compositions. The compositions comprise certain triazine corrosion inhibitors.
U.S. Pat. No. 4,683,071 discloses antifreeze, hydraulic and metal-working functional fluids that contain a mixture of a certain tolutriazole compounds.
There remains a need for improving antifreeze compositions, especially regarding prevention of corrosion of metals and in preventing hard water deposits. The metal to be protected is for example aluminum and the deposits are for example calcium salt deposits.
Surprisingly, it has been found that the present antifreeze compositions are especially effective towards these ends.